1: 72(t) applies only to IRAs. To use 72(t) you roll your qualified plan into an IRA first. 457 withdrawls are out of my realm.
2: For someone else, although I'd like to know what bankruptcy protection for IRAs and 401(k)s is while they're at it.
3: WRT 401(k)s, 403(b)s and 457s I got the impression from the IRS you could rollover while employed but got the impression from my employer/trustee that I couldn't. I haven't investigated further, but I've seen where employers/trustees avoid volunteering information which may encourage you to take your money out of their plan without buying an annuity. (I wonder why... :
) So further investigation is warranted I think.
4: Generally speaking, tax-deferred retirement savings is far more powerful than after-tax savings. I don't know the 457 rules, but I'm fairly sure 457s and 403(b)s are "qualified plans" and can be rolled into an IRA for 72(t) if there isn't a better pre-59.5 withdrawal method in the original plan.
Disclaimer: I'm certainly not an expert at this stuff, and individual situations may vary. I'm comfortable enough with my knowledge and situation that I plan to use my 401(k) as my primary retirement vehiclle and roll it into my IRA whenever changing jobs with the intention of using 72(t) when the time comes.